1. Field of the Invention
The present invention relates to a developing apparatus, a developing processing method, a developing processing program, and a computer readable recording medium recording the program, for performing developing processing on a substrate having been coated with a resist and subjected to exposing processing.
2. Description of the Background Art
For example in manufacturing a semiconductor device, a circuit pattern is formed by what is called the photolithography technique. Specifically, a prescribed film is deposited on a wafer that is a substrate to be processed and, thereafter, a photoresist solution is coated thereon to form a resist film. The resist film is exposed corresponding to a circuit pattern, and then subjected to developing processing. In the photolithography technique, the wafer that is a substrate to be processed is subjected to a series of processing including main steps of: cleaning processing→dehydration baking→adhesion (hydrophobizing) processing→resist coating→pre-baking→exposing→developing→post-baking, so that a prescribed circuit pattern is formed at the resist layer.
In a conventional developing apparatus, for example as shown in FIGS. 13A-13C, a wafer W is horizontally held over a substrate holding portion 51, and a developing solution nozzle 52 is arranged such that its small diameter discharge port is located slightly higher than the surface of wafer W.
Then, wafer W is rotated around a vertical axis, and developing solution nozzle 52 is moved in a radial direction relative to the rotational axis of wafer W while a developing solution is discharged form developing solution nozzle 52. This causes the developing solution to be accumulated on the surface of wafer W in a spiral manner (FIG. 13A).
Then, wafer W with developing solution 53 accumulated on its surface is left for a predetermined developing time, e.g., 60 seconds, to cause the stationary development (referred to as the stationary puddle scheme) (FIG. 13B). Thereafter, a rinse liquid 55, e.g., pure water, is supplied to the center of wafer W from a rinse liquid nozzle 54 (FIG. 13C). As a result, the portions of the resist insoluble in the developing solution remain, forming a prescribed resist pattern (see Japanese Patent Laying-Open No. 07-263302, for example).
However, the developing method described above referring to FIGS. 13A-13C suffers from the following problem. Specifically, when the resist processing is performed by the stationary puddle scheme disclosed in Japanese Patent Laying-Open No. 07-263302, as the resist is generally hydrophobic, a pullback phenomenon, i.e., drops of solution on wafer W pulling at each other by surface tension, occurs if the amount of developing solution accumulated on wafer W is too small. As a result, some portions may not be developed (may not be coated with the developing solution). To overcome this problem, it has been necessary to supply the surface of wafer W with a large amount of developing solution, so that the entire surface is covered with the developing solution regardless of drops of solution pulling at each other by surface tension. As a result, the amount of developing solution being used has been great.
One of solutions for the foregoing problem is a developing processing method disclosed in Japanese Patent Laying-Open No. 2005-210059, in which a wafer is rotated around a vertical axis, and a developing solution nozzle is moved from the outside of the wafer toward the central portion of the wafer while a strip-like developing solution extending in a radial direction relative to the rotational axis of wafer W is discharged from a nozzle discharge port. This causes the developing solution to be coated on the surface of the wafer in a spiral manner.
According to the method, by setting the longer width of the discharge port to be greater, wide strips of developing solution can be aligned in the radial direction of the wafer without any gap, whereby the developing solution can easily be coated on the entire wafer. By setting the shorter width of the discharge port to be smaller, the thickness of the developing solution coated on the wafer surface can be reduced. As a result, the consumption amount of the developing solution can be reduced.
Furthermore, according to the developing method disclosed in Japanese Patent Laying-Open No. 2005-210059, not the stationary puddle scheme but a puddleless scheme (rotary developing scheme) is employed, in which rotation of a wafer is continued during development and a developing solution is supplied to the center of the wafer until the development is finished. According to the puddleless scheme, by the rotation of the wafer (centrifugal force), the dissolved components of the resist can be removed together with the developing solution during the development while a new resist is constantly supplied. Thus, the developing processing can proceed efficiently.